Preparation And Characterization Of The Polystyrene / Silver Core-shell Structure Nano-microspheres

In this paper,we adopted "two-step process" and "insitu polymerization" to prepare PS/Ag core-shell Nanoparticles.We discussed their experimentation method and mechanism,as well as,the action of nickel plating layer was still studied(plating nickel at the surface of PS helps to advance the link force.The two-step process is firstly PS microparticles prepared in latex are sensitize and activation.Then the liquid with Ag are added in the PS with unending stirring.At last PS/Ag core-shell Nanoparticles are fabricated.Insitu polymerization is to synthesize PS/Ag core-shell in the same pot with insitu revert way.The products were characterized by transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM) and Ultra Violet-visible light spectrograph(UV-vis).The results shows:The PS microparticles we prepared are only 30-40nm,PS/Ag core-shell Nanoparticles prepared by "two-step way" are 45-350nm,the shell of Ag can be controlled freely.The figure of PS/Ag core-shell nanoparticles by insitu polymerization are anomaly and reunite heavily.We analyze and bring forward the synthesize mechanism of "two-step method":Firstly, (NH₄) ₂S₂O₄ arose the polymerization of AA and St,at the surface of these PS particles, there are a great deal electronegative SO4^2- and COO^-,the Sn²⁺ with positive electricity were adsorbed at the surface of PS.When PbCl₂ were added,Sn²⁺ and Pb²⁺ response: Sn²⁺+Pb²⁺→Sn⁴⁺+Pb.Then the liquid with Ag are added,so Ag particles gradually aggregate at the surface of PS with Pd as crystal seed.In this way,the Ag layer was thicker and thicker.